The present invention relates to a data communication technology, and more particularly, to a controller capable of adaptively adjusting the speed or data rate of communication. Embodiments of the invention include controllers capable of adjusting communication speed, data storage devices including such a controller, and data communication systems including such a data storage device.
The hard disk drive (HDD) is a conventional, magnetic storage device that is highly competitive on a price per stored data basis. The HDD is capable of storing a large volume of data, but data access (read/write) speeds are not exceptional. However, due to low manufacturing costs, HDDs are widely used as bulk data storage units.
The HDD generally reads/writes data from/to a rotating magnetic disk (or recording medium) using a mechanical read/write head. The mechanical nature of the read/write head and its constituent movable components suffer from such problems as a vibration, noise, heat build-up and the resulting operating distortion, mode-specific disturbance issues, complexity of manufacture, and increasing cost as size constraints become more severe. HDDs also require a relatively long time to retrieve stored data, as the disk must be mechanically rotated to the sector storing the requested data and the read/write head must be moved over the sector. Increasing the data access speed of HDDs requires faster operating speeds for disk rotation and read/write head movement. Unfortunately, such increases tend to consume more power and aggravate some of the foregoing problems, such as noise and heat.
Particularly in the context of small, portable, electronic host devices, a data storage device is required that provides better data access speeds with reduced power consumption.